1. Field of the Invention
The present invention relates to a piezoelectric generator mounted with a crystal oscillator for obtaining reference signals for the control of radio communication apparatuses, portable telephones, pagers, cordless telephones, audiovisual apparatuses, etc.
2. Description of the Prior Art
In piezoelectric generators that are used in the field of mobile radio communication such as radio communication apparatuses, portable telephones, etc., a crystal oscillator and an electronic component (active element) for its oscillation are stored in a container, in general.
With the oscillation element and the electronic component thus stored in one container, an organic substance from a resin-based adhesive that is used to fix the electronic component may adhere to the oscillation element, thereby lowering its oscillation properties.
An example of prior art which solves this problem is explained below with reference to FIGS. 1A and 1B.
An oscillator sealing chamber 6a is provided on one side of a multi-layer ceramic substrate 3a, and a crystal oscillator plate 4a is placed in the sealing chamber 6a and hermetically sealed by means of a lid 5a. Printed patterns and circuit elements 2a that form a generator circuit are arranged on the other side of the multi-layer ceramic substrate 3a or on the side opposite to the oscillator chamber 6a, and are covered by means of a casing 1a that has an adjusting hole 8a. Thereupon, a generator is formed. This generator is mounted on a motherboard by means of reflow electrodes 7a that are provided on a side face of the ceramic substrate 3a. 
In the generator described above, the oscillation element is first mounted in the chamber on the one side and subjected to frequency regulation, and its opening is then sealed. Then, an electronic component is mounted on the other side and loaded with temperature compensation data. However, a mounting surface that carries the electronic component thereon is exposed in the upper surface. In case where the mounted electronic component is damaged, therefore, the previously mounted oscillation element, as well as the electronic component, have to be scrapped together with the container, so that the cost increases. Thus, in order to make the electronic component inaccessible, it has to be concealed with a casing.
To deal with the problem, proposed is a generator that is designed so that no organic substance from the resin-based adhesive for the electronic component fixation can adhere to the oscillation element and that the electronic component or oscillation element can be reused as a non-defective if it is damaged. An outline of this generator will now be described with reference to FIGS. 2A and 2B.
A first container 1b, which is formed of a laminate of ceramic sheets, is molded in the shape of an open-topped box. An active element 2b, an electronic component formed of a bare chip, is fixed in the container 1b with an adhesive.
An oscillation unit 3b is attached to the upper surface of an outer peripheral wall 4b of the first container 1b so as to cover an opening of the container 1b. The oscillation unit 3b, which is formed of a laminate of ceramic sheets, includes an open-topped second container 5b, an oscillation element 6b formed of a crystal oscillator mounted in the second container 5b, and a metallic shielding plate 7b that covers an opening of the second container 5b. By welding the shielding plate 7b to the second container 5b, the oscillator element 6b is hermetically sealed in the second container 5b. 
Two semicylindrical notches 10b are formed on each of two opposite sides of an outer peripheral wall 8b of the second container 5b. Second connecting electrodes 11b1 to 11b4 are formed on the respective inner surfaces of the notches 10b and the bottom face continuous therewith (connecting electrodes 11b2 and 11b3, which are located on the back side in FIG. 2A, are not shown). The electrodes 11b1 and 11b3, among the four second connecting electrodes 11b1 to 11b4, are connected electrically to the oscillator element 6b, while the electrodes 11b2 and 11b4 are connected electrically to a seam ring 9b and grounded.
On the other hand, the active element 2b that is mounted on the first container 1b is connected electrically to electrodes 13b by means of wires 12b. First connecting electrodes 14b1 to 14b4, which are connected to any of the electrodes 13b, are provided individually in four positions on the outer peripheral wall of the first container 1b. The first connecting electrodes 14b1, 14b2, 14b3 and 14b4 are connected electrically to the second connecting electrodes 11b1, 11b2, 11b3 and 11b4, respectively, by means of a conductive adhesive material such as solder. Thus, the oscillation 6b and the active element 2b are connected electrically to each other.
After the electrical connection between the first and second electrodes 14b1 to 14b4 and 11b1 to 11b4 is completed, a bond sealing resin 15b is applied to the outer peripheral portion of the bottom face of the second container 5b, whereupon the second container 5b is fixedly bonded to the upper surface of the outer peripheral wall 4b of the first container 1b. Thus, the top opening of the first container 1b is sealed with the second container 5b to protect the active element 2b. 
Semicylindrical notches are formed in the outer peripheral surface of the outer peripheral wall 4b of the first container 1b, and electrodes 16b01 to 16b14 are provided in the notches, individually. Among these electrodes, the electrodes 16b02, 16b06, 16b09 and 16b13 are also formed in the bottom face of the first container 1b that are continuous with the notches. The electrodes 16b02, 16b06, 16b09 and 16b13 are an AFC terminal, grounding terminal, oscillation output terminal, and power terminal, respectively. The other electrodes are inspection electrodes, which are situated at a given upward distance from the bottom face of the first container 1b. These electrodes are used for data loading in a memory in the active element 2b and various inspections.
According to the prior art described above, however, the active element and the oscillation element are mounted in the first and second containers, respectively, which are stacked in layers to form a double-deck package, so that the overall thickness of the generator is inevitably great.
Although the electrodes for external connection that are formed in the notches of the outer peripheral wall of the first container and the bottom face thereof are situated at the given upward distance from the bottom face, the distance is very short, and the inspection electrodes are located directly adjacent to them. If the electrodes for external connect are soldered to patterns of the motherboard or the like, solder may flow and cause a short circuit.
A piezoelectric generator in an aspect of the present invention comprises an oscillator package, including a piezoelectric oscillator sealed in a container and electrodes for external connection formed on the surface of the container, and an electronic component mounted integrally on the oscillator package. The electronic component is mounted on the same surface of the container that carries the electrodes for external connection thereon.